[88ls1blazer]

I will listen today, but I have never noticed this sound (and not to toot my own horn, but I am pretty observant to out of the ordinary sounds in cars) so it might just be something I am accustomed to. obviously you are under very light throttle as you state the doors lock in second. it actually happens around 7-8 mph even if you are in first, but being you are already in second that tells me you are very light on the throttle. That might make a difference as I am usually that light on the throttle...